Chapter 6: Reproduction in Animals

Science • Class 8

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Chapter Analysis

Intermediate15 pages • English

Quick Summary

The chapter 'Reproduction in Animals' introduces the importance of reproduction for the continuation of species and covers two main modes of reproduction: sexual and asexual. Sexual reproduction involves the fusion of male and female gametes, resulting in the formation of a zygote, which develops into a new individual. Asexual reproduction, found in organisms like hydra and amoeba, does not involve gamete fusion and includes processes like budding and binary fission. The chapter also explains the differences between viviparous and oviparous animals and covers topics like fertilization, embryo development, and metamorphosis.

Key Topics

  • Sexual reproduction
  • Asexual reproduction
  • Fertilization processes
  • Viviparous and oviparous animals
  • Embryo development
  • Metamorphosis
  • Structures of reproductive systems
  • Cloning in animals

Learning Objectives

  • Understand the importance of reproduction in animals
  • Identify the processes involved in sexual and asexual reproduction
  • Differentiate between viviparous and oviparous animals
  • Describe the process of fertilization and embryo development
  • Explain the concept of metamorphosis
  • Recognize the ethical considerations in cloning

Questions in Chapter

Explain the importance of reproduction in organisms.

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Describe the process of fertilisation in human beings.

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Choose the most appropriate answer. (a) Internal fertilisation occurs (i) in female body. (ii) outside female body. (iii) in male body. (iv) outside male body.

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Indicate whether the following statements are True (T) or False (F). (a) Oviparous animals give birth to young ones. (b) Each sperm is a single cell. (c) External fertilisation takes place in frog.

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Give two differences between a zygote and a foetus.

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Define asexual reproduction. Describe two methods of asexual reproduction in animals.

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In which female reproductive organ does the embryo get embedded?

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What is metamorphosis? Give examples.

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Differentiate between internal fertilisation and external fertilisation.

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Additional Practice Questions

What are the main differences between sexual and asexual reproduction?

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Answer: Sexual reproduction involves the fusion of male and female gametes resulting in genetic variation, while asexual reproduction involves a single parent and produces genetically identical offspring.

Describe the process of metamorphosis in frogs.

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Answer: Metamorphosis in frogs involves the transition from egg to tadpole, followed by significant changes leading to the adult frog form.

Explain the role of the zygote in reproduction.

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Answer: The zygote is the fertilized egg that undergoes multiple cell divisions and differentiation to form an embryo, leading to the development of a new organism.

How do environmental factors influence external fertilisation?

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Answer: Factors such as water temperature, salinity, and presence of predators can impact the success rate of external fertilization, as eggs and sperms are exposed to external conditions.

Identify the key structures in the human reproductive system involved in fertilization.

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Answer: In males, key structures include the testes, sperm ducts, and penis. In females, they include the ovaries, oviducts, and uterus.

Discuss the advantages and disadvantages of viviparity.

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Answer: Viviparity, where animals give birth to live young, allows for protection of the embryo and stable internal conditions but usually results in fewer offspring and requires more energy from the parent.

What are the implications of cloning in animals?

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Answer: Cloning can produce genetically identical organisms, which can have uses in medical research and agriculture, but it also raises ethical concerns and risks of abnormalities.

Explain the concept of budding in hydra.

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Answer: Budding in hydra is a form of asexual reproduction where new individuals develop from outgrowths or buds on the parent organism.

What factors ensure the success of internal fertilization?

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Answer: Internal fertilization is successful due to direct transfer of sperm into the female body, protecting gametes from environmental hazards, thus increasing chances of zygote formation.

Describe how gametes differ in structure and function.

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Answer: Male gametes (sperm) are motile with tails for movement, while female gametes (ova) are larger, non-motile, and contain nutrients for the developing zygote.

NCERT Exemplar

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Practice with NCERT Exemplar problems and solutions for this chapter. Exemplar problems are designed to help you master the concepts with advanced-level questions.

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